Can you play multiplayer on the same xbox? On the back it says that you can play with 3 friends on co-op missions or battle head-to-head against 15 opponents in the most action-packed gameplay over xbox live and link play. It also says on the back players 1-4 and system link 2-16. I can't figure out how to get it onto multiplayer. If you know please send the answer right away, it would be greatly appreciated! Thanks.